The invention relates generally to surface mounted connectors, and more specifically, to an electrical connector having contacts arranged in a grid for mating with pads on an electrical device.
The ongoing trend toward smaller, lighter, and higher performance electrical components and higher density electrical circuits has led to the development of surface mount technology in the design of printed circuit boards and electronic packages. As is well understood in the art, surface mountable packaging allows for the connection of the package to pads on the surface of the circuit board rather than by contacts or pins soldered in plated holes going through the circuit board. Surface mount technology allows for an increased component density on a circuit board, thereby saving space on the circuit board.
The ball grid array (BGA) and land grid array (LGA) are two types of surface mount packages that have been developed in response to the demand created by higher density electrical circuits for increased density of electrical connections on the circuit board. The ball grid array includes an array of connections on the bottom side of the package. In the ball grid array, pins extending into the circuit board are replaced by small solder balls placed on the bottom side of the package at each contact location. The circuit board, rather than having holes, has an array of contact pads matching the solder ball placements on the package bottom. Connections are made by reflow soldering the solder balls to mechanically and electrically engage the package to the circuit beard. The land grid array is similar to the ball grid array except that, rather than the application of solder balls, a land grid array socket applies sufficient normal force on the package to mate the package on flexible contact beams in a connector.
BGA and LGA technology offer the advantages of higher connection densities on the circuit board and higher manufacturing yields which lower product cost. However, they are not without disadvantages. In particular, during the development of chips, chip sockets, multi-chip modules (MCM's), and other electronic packages using BGA technology, the resolution of errors of faults requires soldering and unsoldering of the packages which, in the case of ball grid array devices, is particularly difficult. To aid in problem diagnosis, shorting bridges are sometimes used to short between solder balls. However, shorting bridges are expensive to manufacture and difficult to implement.
A need exists for a connector that can be easily and economically manufactured and which enables errors or faults between contacts to be simulated to facilitate the resolution of actual faults and errors.